Relay



F. A. ZUPA June 20, 1944;

RELAY Filed. Sept. 25, 1942 Patented June 20, 1944 RELAY Frank A. Zupa,New York, N. Y., assignor to Bell Telephone Laboratories, Incorporated,New York, N. Y., a corporation 01 New York Application September 23,1942, Serial No. 459,391

Claims.

This invention relates to relays and more particularly to relays for usein the circuits of telephone systems.

It is often necessary that certain relays of a telephone system beresponsive to alternating current, as for example, a relay whichresponds to ringing current incoming over a trunk for signaling thepresence of an incoming call on the trunk. Relays which have been usedheretofore for this purpose, in order to secure adequate sensitivity,have been especially designed with relatively low contact pressures andwith single contact springs.

It has been found desirable to provide a relay having as greatsensitivity as those previously used but with greater contact pressuresand with contact springs having twin contacts of the type generallyprovided in standard direct current relays employed in telephonecircuits whereby more reliable circuit controls may be secured. A relayof the direct current type, such as is disclosed in Patent No. 2,294,327granted to me on August 25, 3,942, does have adquate contact pressuresand twin contacts but cannot be operated effectively in response toalternating current.

It is the object of the present invention to so modify a relay of thisdirect current type that it may be responsive to alternating current tomaintain its contacts firmly engaged without any tendency to' chatter.This object is attained by dividing the forward cross reach of thearmature into two magnetically separated but nonmagnetically joinedsections, one of which is surrounded by a short-circuited coil or coppersleeve to provide a phase displacement of the flux in one section of thearmature with respect to the other section.

The invention will be more readily understood from the followingdetailed description taken in connection with the accompanying drawingin which:

Fig. 1 is a top plan view of a relay of the direct current typeher'einbefore referred to, modified in accordance with the presentinvention;

' Fig. 2 is an enlarged front end view of the relay shown in Fig. 2;

Fig. 3 is a detail view of the armature of the relay showing the mannerin which the armature is divided into magnetically separated sectionsand the manner in which a phase displacement of the flux in one sectionof the armature with respect to the other section is secured; and

Fig. 4 is a sectional view of the front end of the armature as viewedalong section line 4-4 of Fig. 3.

As hereinbefore stated the relay disclosed in the drawing is of thegeneral type disclosed in Patent No. 2,294,327, granted to me, andconsists of a core I secured at its rear end to a mounting bracket 2, anenergizing coil 3 surrounding the core having front and rear spoolheads4 and 5 of insulating material, an armature 6 the forward cross reach ofwhich cooperates with the enlarged pole face I of the forward end of thecore I and the rear ends of the legs 8 and 9 of which are pivoted bypivot pins in to the forwardly extending arms of the mounting bracket 2,reed springs ll, coil terminal lugs l2, a spring pile-up on each side ofthe relay coil 3 each comprising suitable contact springs such as l3,l4, l5, l6, etc., and a back-stop structure comprising the screw l'lsecured to the forward end of the core I and the back-stop nut I8threaded thereon.

The reed springs II, coil terminal lugs l2 and the springs of the springpile-ups are suitably clamped to the mounting bracket 2 by screws l9 and20 which pass through holes in the clamping plates 2!, insulating strips22, the bracket 2, the reed springs ll, insulating strips 23 and thesprings of the spring pile-ups into threaded holes in the clampingplates 24. Terminal lugs I2 and the springs of the spring pile-ups areinsulated from each other and from the bracket 2 by the interposedinsulating strips 22 and 23 and the screws l9 and 20 are surrounded bythe usual sleeves of insulating material (not shown) where they passthrough the holes in the terminal lugs and the springs of the springpile-ups. For enabling the movable springs of the spring pile-ups to bemoved with respect to the fixed springs, studs of insulating material,such as studs 25 and 26, are ring-staked to certain of the movablesprings with the outer ends of the studs 26 engaged against the legs ofthe armature 6.

In accordance with the present invention, the forward cross reach 21 ofthe armature 6 is severed by a slot 28 and the two severed sections arereunited by a plate 29 of non-magnetic material riveted or otherwisesecured to both sections whereby the two sections are firmly securedtogether but magnetically separated by an intervening narrow air-gap.The leg 8 of the armature is surrounded by a sleeve 30 of goodelectrically conductive material, such as copper, which, in effect, is ashort-circuited. winding. In place of the sleeve, a low resistancewinding short-circuited upon itself could be used. To minimize chatteror vibration on the alternating current operation of the relay the poleface of the armature at the point of engagement with the pole face I ofthe core i is provided with an embossment II. The embossed portion Ilmay be an integral part of the armature and formed when the armature isstamped out or may be a separate insert either magnetic or non-magneticmaterial. The embossment may be formed instead on the pole face I of thecore I.

The division oi the armature into two malnetioally separated sections ineffect provides two separate armatures which mechanically function as asingle armature since they are rigidly united by the plate 29 but whichmagnetically function as separate armatures. The copper sleeve Illsurrounding the leg I or one of the sections serves to produce a phasedisplacement oi the flux in that section or the armature with respect tothe other section. For example, assuming the coil 3 to be energized inresponse to one polarity of the alternating current and the armature Ito be in its attracted position and the energizing current changespolarity, then when the current passes through the zero point in itschange irom one polarity to the other, the flux in one section of thearmature having the leg 5, will decay rapidly but due to theshort-circuited sleeve 30 the flux in the section oi the armature havingthe leg B will be retarded in its decay sufficiently to hold thearmature attracted until a flow of flux is again established in theopposite direction in both sections of the armature upon thereenergization oi the coil 3 in response to the opposite polarity of theenergizing current. At this time flux flow in the unsleeved section ofthe armature will build up rapidly and beiorc a reversal of flux flow isproduced in th sleeved section 01' the armature.

It is thus apparent that by a very simple modiflcation of the armatureor an eiilcient direct current type relay, such a relay may be convertedfor alternating current operation and that since the direct currentrelay has adequate spring pressures and twin contacts on all or itssprings, a very reliable and eflicient alternating current relay is madavailable.

What is claimed is:

1. In an electromagnetic device, a heel-piece, a core secured thereto, acoil surrounding said core, an armature hinged to said heel-piece withits free end attractable toward said core upon the energization of saidcoil, said armature being divided into two magnetically separatedsections and a short-circuited coil surrounding one 01 said sectionswhereby a phase displacement or the flux in that section with respect tothe other section is secured to render said device eilectively operableby alternating current.

2. In an electromagnetic device, a heel-piece, a core secured thereto, acoil surrounding said core, a U-shaped armature having its forward crossreach positioned for attraction toward the pole face oi the iorward endof said core upon the energization or said coil and having the ends ofits legs hinged to said heel-piece, said am ture having its cross reachsevered by a slot to divide said armature into two magneticallyseparated sections, a plate of non-magnetic material secured to the twosections of the cross reach to non-magnetically Join said sections, anda copper sleeve surrounding the leg of one of said sections whereby aphase displacement of the flux in that section with respect to the othersection is secured to render said device eflectively operable byalternating current.

3. In an electromagnetic device, a heel-piece, a core secured thereto, acoil surrounding said core, a U-shaped armature having its forward crossreach positioned for attraction toward the pole iace oi! the iorwardtree and of said core upon the energization of said coil and having theends of its legs hinged to said heel-piece, said armature having anembossed portion on its pole lace opposite the pole lace of said coreand having its cross reach severed by a slot forming an air-gap todivide said armature into two mag netically separated sections, a plateof non-ma?- netic material secured to the two sections of said crossreach to non-magnetically join said sections, and a copper sleevesurrounding the leg of one of said sections whereby a phase displacement of flux in that section with respect to the other section issecured to render said device atiectively operable by alternatingcurrent.

a. In an electromagnetic device, a heel--piece, a core secured thereto,a coii surrounding said cor-c, an L-shaped annaturo hinged to saidheeluiece at one side oi said core, a second L-shoped armature,surrounded by a copper sleeve, hinged to said heelmiece at th other sideoi" said core, the short legs of said armatures joined by a plate ofnon-magnetic material, whereby said arms tures are forced to move at thesame time in response to energization oi said coil, the sleeve on saidsecond armature causing a phase displacement of the flux in thatarmature with re spect to the flux in the other armature, to render saiddevice effectively operable by alternating current.

In an electromagnetic device, a. heel-piece, a core secured thereto, acoil surrounding said core, an L-shaped armature hinged to said hee1-piece at one side of said core, a second L-shaped armature hinged tosaid heel-piece at the other side of said core, said second armaturesurrounded by a copper sleeve and carrying an. embossed lug iorcontrolling the extent of motion of said armature, the short legs ofsaid armatures joined by a plate oi non-magnetic material, whereby saidarmatures are forced to move at the same time in response toenergization of said coil, the sleeve on said second armature causing aphase displacement oi the flux in that armature with respect to the fluxin the other armature, to render said device effectively operable byalternating current.

FRANK A. ZUPA.

